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ACERACEAE(Maple family)
Two genera comprising 111 species of trees and shrubs are found in northern temperate regions and on mountains in tropical regions (Mabberley 1987). Acer palmatum Thunb. and other species are often planted as ornamental trees and shrubs. They are also popular as subjects for bonsai, a natural art form produced by artificially stunting the growth of the specimen. Many species yield good timber. Acer saccharum Marshall and other species in eastern North America yield maple syrup. The pollens of the anemophilous species, less commonly the amphiphilous and entomophilous species, are minor causes of pollinosis (Wodehouse 1971). Inhalation of fungal particles from maple bark (Acer L. spp.) can cause maple bark disease, a form of allergic alveolitis (Seaton & Morgan 1984). Contact with the wood and also the pollen of some species may have on occasion produced dermatitis. Species of Acer L., Tilia L. (fam. Tiliaceae), and certain other deciduous trees may become heavily infested with aphids living on the undersides of the leaves. Whilst feeding, these insects excrete a sugary liquid known as honeydew which falls from the trees as a fine rain. Large numbers of aphids may also fall from the trees. A case has been described where an elderly woman with suspected delusions of parasitosis (Ekbom's syndrome) who, after unknowingly sitting under a species of Acer during the summer months, complained of a sticky feeling and a crawling sensation caused by green insects on her skin (Mitchell 1975). Maple is said to be a sensitising wood by (Weber 1953), repeated by (McCord 1958). The seeds are covered with spiny hairs that can penetrate and irritate the skin (Hebda 2003). The pollen of this and another species of maple has been implicated as a cause of airborne contact dermatitis by Lovell et al. (1955) who observed positive patch test reactions to "box elder pollen oil" and to "maple pollen oil" in two patients. Nadkarni (1976) states that the leaves of this species are irritant. The wood was listed as irritant by (Hanslian & Kadlec 1966), probably from (Weber 1953). An extract of the bark has been used for its astringent effect in the treatment of sore eyes by North American Indians (Wren 1975). This species has been found to contain 2,6-dimethoxy-1,4-benzoquinone which is a known contact allergen (Hausen 1978a). References
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